Degradation Of Methyl Orange Dye Research Articles

Experimental and density functional theory investigation on one- and two-dimensional coordination polymers and their ZnO-doped nanocomposite materials for wastewater remediation

Two Cd(II) and Cu(II) coordination polymers (CPs) with the compositions of [Cd(HIPA)(HIZ)(H2O)2]n·3H2O (CP1) and [Cu(HIPA)(HIZ)2]n·2H2O∙MeOH (CP2), where, (H3IPA = 5-hydroxy isophthalic acid, and HIZ = imidazole), were successfully obtained by the reaction of the mixed ligand of H3IPA and HIZ under solvothermal conditions. The prepared CPs were characterized by X-ray diffractions (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–visible spectroscopy, thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) analysis, and microscopic (TEM and SEM) techniques. The complexes 1 and 2 shows dual behavior as adsorbent and photocatalyst for the adsorption and photocatalytic degradation of methyl blue (MB), methyl orange (MO), and crystal violet (CV) dyes. Additionally, zinc-oxide doped composite materials (ZnO@CP1 and 2) were also synthesized using solvothermal and mechanochemical solid grinding methods. Compared with the parent coordination frameworks (CP1 and CP2), the composites (ZnO@CP1 and 2) exhibited slightly improved surface area with reduced photogenerated electron-hole ratio, hence displayed good photo degradation activity. Moreover, the density functional theory (DFT/B3LYP) with the counterpoise and dispersion corrections was employed to validate dyes adsorption mechanism with the reported CPs.

Enhanced visible light catalytic activity of holey Ti3C2 based catalyst for azo dyes

The efficient degradation of organic dye pollutions is of great importance for environmental remediation. In this work, we prepared holey Ti3C2 (H-Ti3C2) and further synthesized H-Ti3C2/Ag/AgX (Cl, Br, I) Schottky catalysts by a simple electrostatic self-assembly method, and found that H-Ti3C2 could significantly improve the catalytic activity and stability of AgX. The H-Ti3C2/Ag/AgX composites showed great visible light absorption, obvious photocurrent intensity, and high charge transfer efficiency, ultimately improving photocatalytic efficacy for the degradation of methyl orange (MO) dye. The composite (5 wt%) H-Ti3C2/Ag/AgBr has the greatest photocatalytic activity, degrading 99.2% of the MO solution after 40 min of visible light irradiation, which is 1.08 and 2.02 times more than (5 wt%) Ti3C2 /Ag/AgBr and Ag/AgBr, respectively. The photocatalytic performance of H-Ti3C2/Ag/AgBr for MO dyes remains at 51% after five cycles. This result indicates that combining H-Ti3C2 with other photosensitive semiconductors to improve the catalytic activity and stability offers great possibilities. The present work not only provides a simplified method for the preparation of H-Ti3C2/Ag/AgX composites, but also offers a great possibility for H-Ti3C2 MXene as a co-catalyst to increase the photocatalytic degradation efficiency of organic pollutants.

Enhancement of bifunctional photocatalytic activity of boron-doped g-C3N4/SnO2 heterojunction driven by plasmonic Ag quantum dots

Enhancement of photocatalytic charge transfer with reduced electron–hole (e− + h+) recombination toward the targeted chemical reaction is a challenging task. In this study, we utilized boron (B) dopant as impurity levels, and the plasmonic Ag quantum dots (QDs), and g-C3N4/SnO2 heterojunction nanocomposite under visible light (λ = 385–740 nm) as a nanocomposite photocatalytic system for energy and environmental applications. The introduction of B dopant with optimal level (BCN1.0) of 1 wt% resulted in the fast migration of photoexcited electrons from valence band to the conduction band of g-C3N4 and reduced the migration distance of the electrons from valence band to the conduction band and improved surface redox reactions. The heterojunction formed with SnO2 nanorods and nanoparticles enhanced the electron–hole transfer rate across the interface of the heterojunction (BCNS15) with 15 wt% and improved the photocatalytic activity during redox reactions. The introduction of plasmonic Ag QDs (1 wt%) as a co-catalyst improved the H2 generation efficiency (BCNS–Ag1.0). Ultraviolet photoelectron spectroscopy results confirmed that the charge transfer process was initiated via the Z-scheme mechanism. Photoluminescence spectra identified the reduction of electron–hole recombination that was responsible for improved catalytic efficiency in the optimized heterojunction nanocomposite. The synergetic effect of B dopant, the visible light sensitization effect and the co-catalytic effect of the Ag QDs, the formation of a heterojunction of the B-g-C3N4/SnO2/Ag (BCNS–Ag1.0) nanocomposite resulted in 2.5 times higher methyl orange dye degradation efficiency which is 65.6% compared to pristine g-C3N4 (CN) 25.9%. Further, the photocatalysts were tested for photocatalytic H2 generation, the optimized BCNS–Ag1.0 nanocomposite heterojunction showed 3.2 times higher H2 generation activity (10.2 mmol/h/gcat) than pristine CN(3.1 mmol/h/gcat) through Z-scheme mechanism. Finally, the BCNS–Ag1.0 nanocomposite demonstrated excellent stability toward methyl orange degradation as well as H2 generation for at least 4 cycles. Therefore, the BCNS–Ag1.0 nanocomposite is a promising photocatalytic system for scale-up synthesis.

Photocatalytic Performance of Sn–Doped TiO2 Nanopowders for Photocatalytic Degradation of Methyl Orange Dye

The tin-doped TiO2 powders obtained by sol-gel and microwave-assisted sol-gel methods were investigated. The synthesis took place in a basic medium (pH 10, ammonium hydroxide, 25%) starting from tetrabutyl orthotitanate in its parental alcohol. In the case of the dopant, Tin(II) 2-ethylhexanoate as SnO2 precursor was used in the amount of 1, 2, or 4 mol % SnO2. Based on thermal analysis data, the powders were thermally treated in air, at 500 °C. The comparative investigation of the structure and morphology of the nanopowders annealed at 500 °C was performed by scanning electron microscopy (SEM), high-resolution transmission electron microscopy with selected area electron diffraction (HRTEM/SAED), scanning transmission electron microscopy (STEM) coupled with EDX mapping, Fourier transmission infrared (FTIR), UV–Vis, Raman and photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), and X-ray florescence spectroscopy (XRF). The obtained materials were tested for the photocatalytic removal of methyl orange dye from aqueous solutions. High degradation efficiencies (around 90%) were obtained by Sn doping after 3 h of UV light irradiation.

Elemental semiconductor red phosphorus/ZnO nanohybrids as high performance photocatalysts

The solar energy conversion through the photocatalyst for the pollutant degradation is important effort for development of the visible light photocatalysts for the practical application in various filed. In this work, elemental semiconductor red phosphorus/ZnO nanohybrid (Z-Rp) through simple, cost-effective, and sustainable ball milling approach and further studied its visible light driven-photocatalytic activity towards the pollutant degradation under visible irradiation. The prepared Z-Rp were characterized by the various stereoscopic and microscopic technique which shows improvement of the structural, optical, and physical properties of the zinc oxide after addition of the elemental red phosphorous. The Diffuse reflectance spectroscopy and valence band spectra shows the shifting of the energy band towards the visible light region after incorporating of the red phosphorus which are father supported by the visible light degradation process. The optimized Z-Rp nanohybrids displayed the excellent visible light driven photocatalytic activity toward the methyl orange dye degradation as compared to the bare materials, which further prove the optimal reaction parameter could effectively enhanced visible light photocatalytic activity. This easy fabrication process and inexpensive earth abundant Rp compared to the silver and gold-based plasmonic metal, which are also used to enhance the photocatalytic performance of the metal oxide nanoparticles, can be a good and sustainable approach for the solar energy conversion for various application.

Degradation of Organic Methyl Orange (MO) Dye Using a Photocatalyzed Non-Ferrous Fenton Reaction

Removal of recalcitrant organic pollutants by degradation or mineralization from industrial waste streams is continuously being explored to find viable options to apply on the commercial scale. Herein, we propose a titanium nanotube array (based on a non-ferrous Fenton system) for the successful degradation of a model contaminant azo dye, methyl orange, under simulated solar illumination. Titanium nanotube arrays were synthesized by anodizing a titanium film in an electrolyte medium containing water and ethylene glycol. Characterization by SEM, XRD, and profilometry confirmed uniformly distributed tubular arrays with 100 nm width and 400 nm length. The non-ferrous Fenton performance of the titanium nanotube array in a minimal concentration of H2O2 showed remarkable degradation kinetics, with a 99.7% reduction in methyl orange dye concentration after a 60 min reaction time when illuminated with simulated solar light (100 mW cm-2, AM 1.5G). The pseudo-first-order rate constant was 0.407 µmol-1 min-1, adhering to the Langmuir-Hinshelwood model. Reaction product analyses by TOC and LC/MS/MS confirmed that the methyl orange was partially fragmented, while the rest was mineralized. The facile withdrawal and regeneration observed in the film-based titanium nanotube array photocatalyst highlight its potential to treat real industrial wastewater streams with a <5% performance drop over 20 reaction cycles.

Photodegradation of methyl orange dye by using Azadirachta indica and chemically mediated synthesized cobalt doped α-Fe2O3 NPs through co-precipitation method

In current study, the Co-precipitation method was successfully used for the synthesis of Cobalt (Co) doped hematite (α-Fe2O3) nanoparticles (NPs). The synthesized Co-doped α-Fe2O3 NPs were analyzed by various characterization techniques. The chemical and greenly synthesizedα-Fe2O3 NPs had an average crystallite size of 22.63 and 16.02 nm as analyzed by XRD respectively. The Raman peaks marks the crystalline nature and hematite phase of Fe2O3 nanoparticles. The spherical shape of the Co-doped α-Fe2O3 NPs in both chemical and green methods is determined by the SEM pictures. UV–visible absorption studies marked the values of band gap i.e. 2.28 and 2.61 eV for chemical and green synthesized Co-doped α-Fe2O3 respectively. By employing the use of methyl orange dye, the photocatalytic action of α-Fe2O3 NPs was analyzed. The findings have shown that an appropriate amount of Co-dopant can significantly lead into an increase in the number of hydroxyl radicals produced from α-Fe2O3 NPs. They cause increase the methyl orange dye degradation rate. The results have shown that Azadirachta indica extract has the potential to produce α-Fe2O3-NPs in an environmentally safe manner. This research concluded that the α-Fe2O3 NPs have better photocatalytic potential with aqueous Azadirachta indica leaves extract.

Photocatalytic Degradation of Methyl Orange and Methylene Blue Dyes by Engineering the Surface Nano-Textures of TiO2 Thin Films Deposited at Different Temperatures via MOCVD.

TiO2 thin films were deposited on quartz substrates by metal-organic chemical vapor deposition (MOCVD) at temperatures of 250, 350, and 450 °C. X-ray diffraction (XRD) data revealed the production of a pure anatase phase, a decrease in crystallite size, and a textural change as deposition temperature increased. Atomic force microscopy (AFM) was used to study the morphological properties and confirm XRD results. UV-Vis.-NIR spectroscopy was used to investigate the optical properties of the samples. The effect of deposition temperature on wettability was investigated using contact angle measurements. Sunlight photocatalytic properties increased with the increase in deposition temperature for methyl orange and methylene blue. Films were post-annealed at 500 °C for 2 h. The effect of annealing on all the above-mentioned properties was explored. The kinetic analysis demonstrated superb agreement with the kinetic pseudo-first-order model. The rate of photocatalytic degradation of MB was ~8, 13, and 12 times that of MO using 250, 350, and 450 °C deposited films, respectively. Photodegradation was found to depend on the specific surface area, type of pollutant, and annealing temperature.

In Situ Hydrothermal Synthesis of Ni1-xMnxWO4 Nanoheterostructure for Enhanced Photodegradation of Methyl Orange.

The monoclinic nanocrystalline Ni1-xMnxWO4 heterostructure has been successfully synthesized by the hydrothermal technique for achieving better sensitive and photocatalytic performances. Different characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis), and photoluminescence (PL) spectroscopy have been employed to investigate their structural, microstructural, and optical properties. Mn-ion incorporation in the NiWO4 lattice reduces the particle size of the sample compared with the pure undoped NiWO4 sample, which has been confirmed from the transmission electron microscope image. The Tauc plot of the Ni1-xMnxWO4 sample exhibits a significant decrease in bandgap energy compared with the pure undoped NiWO4 sample due to the quantum confinement effect. Finally, the material was explored as a photocatalyst for the degradation of methyl orange (MO) dye from wastewater under visible light irradiation. Various reaction parameters such as pH, catalyst dose, reaction time, and kinetics of the photodegradation were studied using the batch method. The results showed that the Ni1-xMnxWO4 is highly efficient (94.51%) compared with undoped NiWO4 (65.45%). The rate of photodegradation by Ni1-xMnxWO4 (0.067) was found to be 1.06 times higher than the undoped NiWO4 (0.062).

Facile Synthesis and Fabrication of NIPAM-Based Cryogels for Environmental Remediation.

Herein, polymeric cryogels containing poly(N-isopropylacrylamide) were synthesized by cryo-polymerization at subzero temperature. The synthesized cryogels were loaded with silver and palladium nanoparticles by the chemical reduction method at room temperature using the reducing agent NaBH4. Moreover, for comparison with cryogels, pure poly(N-isopropylacrylamide) hydrogel and its silver hybrid were also prepared by the conventional method at room temperature. The chemical structure and functional group analysis of the pure cryogels was confirmed by Fourier transform infrared spectroscopy. The synthesis of hybrid cryogels was confirmed by the X-ray diffraction technique and energy dispersive X-ray. The pore size and surface morphology of the pure cryogels, their respective hybrid cryogels and of conventional hydrogels were studied by using the scanning electron microscopy technique. The hybrid cryogels were successfully used as a catalyst for the degradation of methyl orange dye. The degradation performance of the hybrid cryogels was much better than its counterpart hybrid hydrogel for methyl orange dye. The effect of temperature and amount of catalyst on catalytic performance was studied by UV-visible spectroscopy. The reduction follows pseudo-first-order reaction kinetics. In addition, the antibacterial activities of these cryogels were evaluated against Gram-positive bacteria (Staphylococcus aureus, ATCC: 2593) and Gram-negative bacteria (Escherichia coli, ATCC: 25922). Both hybrid cryogels have shown much better antibacterial activity for these two strains of bacteria compared to pure cryogels. The results indicate that these cryogels are potential candidates for water purification systems as well as biomedical applications.

Effect of sulfur precursors on hydrothermal growth of MoS2 nanostructures and its visible-light-driven photocatalytic activities

The molybdenum disulfide (MoS2) nanostructures such as nanosheets, nanoflowers, nanoparticles, and nanoflakes are promising candidate materials for environmental pollution control. In this work, the effect of sulfur precursors i.e. thioacetamide, thiourea, and elemental sulfur on the morphology of hydrothermally grown MoS2 material was studied followed by their visible-light-driven photocatalytic activities toward methyl orange (MO) dye degradation at ambient conditions. Interestingly under scanning electron microscope (SEM) images, the morphologies of synthesized materials were seen to consist of systematic nanosheets, aggregates, and agglomerates. Raman spectroscopy and XRD studies suggested that the grown materials were composed of primarily 1T-2H mixed phase of MoS2 along with a minor oxide phase of molybdenum. Moreover, photocatalytic MO dye degradation activities exhibited by thioacetamide-grown MoS2 nanostructures were found to be better than those of elemental sulfur and thiourea counterparts. The kinetic rates of degradation towards MO dye by materials synthesized with thioacetamide, elemental sulfur, and thiourea were found to be 0.00804 min−1, 0.00614 min−1, and 0.00531 min−1, respectively. The relatively better photocatalytic activities exhibited by thioacetamide-grown MoS2 material were attributed to its predominant nanosheet morphology and the presence of a greater amount of MoS2 contents. This work will be helpful for a better understanding of morphological control hydrothermal synthesis of MoS2-based materials and their subsequent organic dye degradation activities.

Degradation of the dye methyl orange using cow and goat milk iron nanoparticles

ABSTRACT Environmental pollution is a global issue, and the contamination of water by dyes is a matter of concern. This work reports an environmentally friendly method for degrading methyl orange dye using iron nanoparticles (INPs) synthesized from pasteurized cow and goat milk and ferric chloride (FeCl3). INPs were synthesized using FeCl3 and milk mixed in a 1:2 (v/v) ratio and subsequently heated at 70 0C. The formation of INPs was monitored by visualizing the color changes. The synthesized NPs were characterized by FTIR, SEM, EDS, TEM, XRD, and XPS. The XRD results showed that INPs were formed and had an amorphous structure. TEM data showed smaller semi-spherical particles with sizes of 8-27 nm, and they were present in an aggregated state. Dye degradation studies were conducted using INP with UV light exposure and H2O2 addition. Both the processes were monitored using UV/Vis scans at different time intervals. The results showed that the degradation of methyl orange was faster in the presence of H2O2 (over 85% efficiency in 60 min) than in the presence of UV light. The current study shows that the INPs formed using milk have the potential to be used as catalysts in azo dye degradation reactions.

Nanostructured Zn0.1Co2.9O4 material: Synthesis, characterization and its applications for energy storage and electrocatalytic dye degradation

This article presents the synthesis and characterization of a cobalt oxide nanomaterial with potential applications in dye degradation and energy storage. The nanomaterial, Zn-doped cobalt oxide (Zn0.1Co2.9O4), was synthesized using a coprecipitation method followed by calcination at 300 °C for 5 h. Various techniques including XRD, TEM, and BET were employed to analyze the phase formation, particle size, morphology, and surface area of the calcined sample. The XRD analysis confirmed the phase purity of the material, revealing a nanocrystalline structure with an average crystallite size of 10 nm. TEM imaging revealed spherical-shaped particles with a mean particle size of 11 nm. The material exhibited mesoporous characteristics, with a surface area of 60 m2/g and a pore size of 33 nm according to BET analysis. Cyclic voltammetry (CV) measurements conducted at different scan rates demonstrated the redox behavior of the material, as evidenced by the presence of oxidation and reduction peaks. Galvanostatic charge–discharge (GCD) experiments revealed a specific capacitance (Cs) of 117 F/g at a current density of 0.1 A/g, which decreased to 78 F/g at 1 A/g. The electrocatalytic dye degradation of methyl orange dye (5 ppm) was carried out using a stainless steel electrode coated with the Zn0.1Co2.9O4 nanomaterial. An applied potential of 15 V and a current of 0.03 A resulted in a 98% degradation of the dye after 30 min. The experiment was repeated for five successive cycles, yielding consistent levels of dye degradation.

Surface-decorated porphyrinic zirconium-based metal-organic frameworks (MOFs) using post-synthetic self-assembly for photodegradation of methyl orange dye.

We report herein the surface decoration of a water-soluble free-base porphyrin, namely, 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin-tetra(p-toluenesulfonate) (H2TMPyP), over three different zirconium-based metal-organic frameworks of different linker structure and functionality; namely UiO66, UiO66-NH2, and MIP-202, via self-assembly. The synthesized MOFs along with the resulting complexes have been characterized via spectroscopic and analytical techniques (XRD, FT-IR, TEM, N2 adsorption/desorption, and laser scanning confocal microscopy). The self-assembly of H2TMPyP with the examined three MOFs was observed by using the steady-state absorption and fluorescence, as well as the fluorescence lifetime studies. It was evident that the highest complex interaction was recorded between porphyrin and UiO-66-NH2 compared with the lowest interactions between porphyrin and MIP-202. This is in good agreement with the high surface area and pore volume of UiO-66 (1100 m2 g-1 and 0.68 cm3 g-1) and compared to that of MIP-202 (94 m2 g-1 and 0.26 cm3 g-1). The photocatalytic activities of the three porphyrin entities immobilized zirconium-based MOFs were compared toward methyl orange dye degradation from aqueous solution under visible light irradiation (λex = 430 nm). The photocatalytic studies render the fabrication of the self-assembled H2TMPyP@UiO-66-NH2 composite as a promising material for dye degradation from polluted wastewater.

Synthesis of NiFe2O4/SiO2/NiO Magnetic and Application for the Photocatalytic Degradation of Methyl Orange Dye under UV Irradiation

NiFe2O4/SiO2/NiO magnetic was successfully synthesized using NiFe2O4, SiO2, and NiO as the core, interlayer, and shell, respectively. NiFe2O4/SiO2/NiO under UV light irradiation was used for photocatalytic degradation of methyl orange dye with different pH, catalyst dose, and initial dye concentration. This composite was characterized by X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), Scanning Electron Microscopy-Electron Dispersive X-ray Spectroscopy (SEM-EDs), Vibrating Sample Magnetometer (VSM), UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS), and Point of Zero Charge (pHpzc). The results showed that the composite is a superparamagnetic material with a saturation magnetization value of 44.13 emu/g. It also has a band gap of 2.67 eV with a pHpzc of 6.33. The optimum conditions for photocatalytic degradation were at pH of 4; 0.50 g/L catalyst dose, and 10 mg/L initial concentration. NiFe2O4/SiO2/NiO degradation efficiency to methyl orange dye was 95.76%. The photocatalytic degradation in different concentrations follows the pseudo-first-order, where the greater the concentration, the smaller the constant rate (k). After five cycles of repeated usage, NiFe2O4/SiO2/NiO has good catalytic performance as well as efficient and favourable of a recyclable photocatalyst. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Efficient photodegradation of methyl orange dye using electrogenerated copper-zinc oxide hybrid

A photoactive Cu-doped ZnO (Cu/ZnO) hybrid was synthesized via a simple electro-generation procedure. The resultant catalyst was then subjected to UV–vis DRS and BET analysis for band gap and porosity properties studies. The photocatalytic efficiency of the Cu/ZnO hybrid was then evaluated via discoloration reaction of dye pollutant, methyl orange (MO) under visible light irradiation. To study the effect of Cu loadings on the hybrid catalyst performance, a series of catalysts with different Cu wt.% were synthesized and tested for MO degradation. As result, ZnO doped with 5 wt% Cu was found as the most active catalyst with 100 % MO removal followed by 3 wt% Cu/ZnO (94 %), 7 wt% Cu/ZnO (71 %) and 10 wt% Cu/ZnO (40 %). Whereas, in the presence of pure ZnO, only 23 % MO was managed to be degraded, remarking its low catalytic reactivity compared to Cu/ZnO hybrids, especially 5 wt% Cu/ZnO. This might be due to the increase in surface area and lower band gap of 5 wt% Cu/ZnO (3.11 eV) compared to ZnO (3.20 eV) as analyzed by BET and UV–vis DRS respectively. Meanwhile, the optimum reaction conditions were found to be pH 3, 10 mg/L initial dye concentration, and 0.38 g/L of 5 wt% Cu/ZnO. Conclusively, the electrogenerated Cu/ZnO catalyst was highly capable of degrading methyl orange dye pollutants and therefore has a high potential for future wastewater treatment application.

Photocatalytic Activity of Defective TiO2-x for Water Treatment/Methyl Orange Dye Degradation

This study is designed to highlight photocatalytic activity of TiO2 nanoparticles in methyl orange (MO) dye degradation. Titanium dioxide TiO2 nanopowder was synthesized by conventional sol-gel method and calcined in air atmosphere at different temperatures 350C, 550C and 850C. The prepared TiO2 nanoparticles then were subjected to a solid state reaction with calcium hydride (CaH2) at the same temperatures but calcined in argon atmosphere. X-Ray Diffraction (XRD) measurements used for phase and crystalline size identification showed that the obtained samples have the same TiO2 anatase phase, but the crystalline size decreased after reduction treatment. The electronic properties obtained via UV spectroscopy showed the decrease in calculated energy gap from 3.3 eV for prepared TiO2-550 to 2.65 eV for reduced TiO2-CaH2-550, which extend the absorption spectra toward visible light region. Energy dispersive spectroscopy (EDS) and scanning electron microscope (SEM) measurements revealed that the particle size decreased after reduction treatment similar to the XRD crystalline size. EDS results indicated that the deficient in oxygen content relates to formation oxygen vacancies responsible for nonstoichiometric TiO2-x oxides formation. The synthesized reduced TiO2 showed an excellent photo-catalytic activity in methyl orange dye degradation under optimum condition: pH 4.5, 40 mg catalyst loading and 10 ppm initial dye concentration.

Precursor-directed approach to fabricate TiO2-gCN composite: An efficient photocatalyst to harness solar spectrum

ABSTRACT In this study the porous composites, in-situ TiO2-g-C3N4 (in-situ TiO2-g-CN), was fabricated by in-situ generation of TiO2 from titanium tetra-oximate during thermal polymerisation of urea into gC3N4. For comparison, TiO2-g-C3N4 composite (TiO2-g-CN) and g-C3N4 (gCN) were also prepared by decomposition of urea in the presence and absence of TiO2 nanoparticles (NPs), respectively. The synthesised composites were characterised by FT-IR, SEM-EDX, TGA, and XRD analyses. The analyses of the samples revealed that the particle size of the composites decreases with the addition of TiO2 precursor, titanium tetra-oximate, during g-C3N4 Synthesis. A comparative study has been conducted on the photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dyes in the presence of in-situ TiO2-g-CN, TiO2-g-CN, and gCN under the solar spectrum. In the presence of in-situ TiO2-g-CN, 99.7% degradation of MB and 68.4% degradation of MO was observed within 100 min, and it is superior as compared to TiO2-g-CN and gCN.

Synthesis, characterization, and photocatalytic degradation of anionic dyes using a novel ZnO/activated carbon composite

Zinc oxide/activated carbon from Thapsia transtagana stems (ZnO/ACTTS) composite demonstrated good photocatalytic properties for removing methyl orange (MO) dye from aqueous solution. This study utilized the chemical activation method using phosphoric acid to prepare activated carbon, which was then used to synthesize the ZnO/ACTTS composites by the hydrothermal technique at different percentages of the amount of ZnO (15, 30, 50 and 75 %). XRD, FTIR, and SEM-EDX were used to characterize the produced composite materials. The photocatalytic degradation of the catalysts was investigated for the degradation of MO dye from aqueous solution. The effects of zinc oxide content, pH of solution, and catalyst dosage were studied. Experimental results indicate that the ZnO/ACTTS (75 %) composite with exhibited good activity under acid pH conditions with an optimal catalyst dosage of 0.5 g/L. Photodegradation kinetics followed a pseudo-second order kinetics. ZnO/ACTTS composite will be a catalyst to degrade a wide range of dyes from the textile industry in the aquatic medium.

Novel green synthesis of N-doped carbon dots from fruits of Opuntia ficus Indica as an effective catalyst for the photocatalytic degradation of methyl orange dye and antibacterial studies

• We have prepared Undoped and N-doped C-dots from Opuntia ficus Indica plant extract. • The synthesized Undoped and N-doped C-dots exhibit, the green fluorescence. • We found higher photocatalytic activity in N-doped C-dots than Undoped C-dots. • N-doped C-dots have utilized as photocatalytic for the degradation of Methyl orange dye. • Further we have study them anti-bacterial activity using gram negative and gram positive bacterias. A carbon dot is an attractive material for the photocatalytic degradation of organic pollutant. Moreover it’s extensively used as a material to control the growth of micro organisms. Herein we are reporting the synthesis of Undoped and N-doped carbon dots (N-CDs) derived from Opuntia Ficus Indica (O.F.Indica) fruits. Further we have well characterized by UV-Vis, FT-IR, XPS spectral, HR-TEM, Raman and XRD techniques. The synthesized Undoped and N-CDs are stable for 3 months. Finally we have found the N-CDs shows the higher photocatalytic activity then Undoped C-dots, due to presence of N-atom. We also have discussed the possible degradation mechanism of Methyl Orange (MO). Finally the N-CDs was utilized their antibacterial activities. We used Streptococcus Pyogenes, Staphylococcus Aureus , Klebsiella Pneumoniae, and Shigella Flexneri. Among them we found Streptococcus Pyogenes a bacterium was largely controlled the growth by our N-CDs.